1. Field of the Invention
The present invention relates to a wireless LAN system, a wireless LAN access point, a wireless LAN terminal and an activation control method useful for them, and more particularly, to a wireless LAN system for activating a wireless LAN (Local Area Network) terminal that is shut down or on standby upon an instruction from a management terminal even in the case of using a security such as IEEE (Institute of Electrical and Electronic Engineers) 802.1x in a wireless section.
2. Description of the Related Art
There is a technology that is called “Wake on LAN”, for example, in the existing LAN. In this technology, to activate a wireless LAN terminal that is shut down or on standby from a remote site, a signal of activation instruction is issued from a management terminal, and if only a wireless LAN module is in the operated condition even when the terminal is shut down or on standby, the wireless LAN module receiving the activation instruction signal sends the activation instruction signal to the terminal mounting the module.
The terminal receiving this activation instruction signal transfers from the shutdown or standby state to the operated state (active state). In this case, there is a technology for implementing the remote management while the security by a password function is maintained, even if the terminal is provided with the password function for preventing the illegal use of the third party (e.g., refer to Japanese Patent Laid-Open Nos. 11-345205 and 2000-215167).
It is pointed out that there is possibility that the data encrypted by a WEP (Wired Equivalent Privacy) key employed for the wireless LAN is analyzed, and also there is danger that all the data communications via the wireless LAN are analyzed because the WEP key is analyzed.
To exclude these dangers as much as possible, it is necessary for the data communication via the wireless base station to make the user authentication named the IEEE (Institute of Electrical and Electronic Engineers) 802.1x authentication (e.g., refer to “6. Principle of operation” (“Port-Based Network Access Control”, IEEE 802.1x, Jun. 14, 2001)). Moreover, there are many cases employing the method of dynamically generating and periodically changing the encryption key for data encryption in the wireless LAN.
In the conventional wireless LAN system, when the security technology for wireless LAN such as IEEE 802.1x authentication is used, the connection is attested by an authentication server, a different encryption key from other terminals is employed in the communication, and the encryption key is renewed regularly. In this technology, there is a case where the activation instruction signal may not be received by the wireless LAN terminal.
When the security technology for the wireless LAN is used, the authentication with the authentication server is implemented, employing a driver and the authentication software of the wireless LAN terminal mounting the wireless LAN module, and a digital certificate provided for the wireless LAN terminal, but can not be achieved only by the wireless LAN module simplex.
Therefore, when the encryption key is renewed while the wireless LAN terminal is shut down or on standby, or when the authentication period expires and the authentication is needed again, the wireless LAN terminal can not communicate with the wireless LAN access point, and receive the activation instruction signal.
Also, in the conventional wireless LAN system, when the security technology for the wireless LAN is used in the environment where there are a plurality of connectable wireless LAN access points, there is a case where the wireless LAN terminal can not receive the activation instruction signal.
When the security technology for the wireless LAN is used, the authentication with the authentication server can not be achieved only by the wireless LAN module simplex, as in the above. Also, the wireless LAN terminal may make a roaming due to movement of the wireless LAN terminal or variations in the ambient environment while the terminal is shut down or on standby.
In this case, the authentication with the authentication server is required in the roaming, but since the wireless LAN terminal is shut down, the authentication with the authentication server can not be achieved, disabling the communication, so that the activation instruction signal cannot be received. The above problems can not be solved using the technologies as described in Japanese Patent Laid-Open Nos. 11-345205 and 2000-215167.